Bug 19039: (follow-up) Results of virtual shelves (lists) not sortable by date

Bug 19039: (follow-up) Results of virtual shelves (lists) not sortable by date

    In the staff client, when viewing the content of a list, it can be sorted by 'title', 'author' or 'call number' but not by 'date added'.

    This patch adds 'date added' as an option for default sorting of lists. It also makes it available as a sorting option while viewing lists.

    Test plan:
    In the staff client and the opac:
    1) View a list containing several items
      => Notice that you can't sort by 'date added'
    2) Try to edit the list or create a new one
      => Notice you can't choose date added as the default sort order
    3) Apply the patch
    4) When viewing the list you should now be able to sort by date added
      => Make sure it orders correctly
    5) Edit or create a list and choose date added as default sorting order
      => Make sure it uses date added as default
      => On the staff client: test that the filter for 'sort by' works for date added
      => On the opac: test that, while viewing the contents, choosing 'default sorting' in the dropdown menu sorts correctly

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>